Dietary fiber is an important nutrient in human and animal nutrition that provides direct physiological benefits to the organism. Among the physiological benefits which dietary fiber has been shown to confer include: laxation; blood glucose attenuation; blood lipid attenuation; satiety; weight-loss; and growth stimulation of beneficial probiotic organisms. Regulatory bodies around the world recognize the beneficial health effects of dietary fiber in human and animal nutrition. As a result, health claims based on the dietary fiber content of food are allowed in most countries around the world.
Food products claiming beneficial dietary fiber content have a competitive advantage in segments of the marketplace. For example, food manufacturers may be able to market their products as healthful and beneficial if the products have appropriate amounts of dietary fiber. This has led many food manufacturers to fortify their food products with various dietary fibers. In many instances, this fortification can add significant cost to the manufacture of the food product. Thus, achieving accurate quantification of all dietary fiber fortified into a food product by analytical methods has significant cost impact for food manufacturers and reduces the need for over-fortification while improving profitability.
For purposes of affirming dietary fiber content for both health claims and nutritional labeling, international regulatory agencies and food manufacturers rely primarily on official methods of the Association of Analytical Chemists (AOAC) International. Among the methods typically used for nutritional labeling are AOAC 985.29; AOAC 991.43; AOAC 991.42; AOAC 993.19; AOAC 2009.01; AOAC 2011.25; and AOAC 2001.03. For all of these official AOAC methods, a glass fritted crucible is used for the isolation and quantification of dietary fiber. During analysis, a sample containing dietary fiber is filtered through the crucible to isolate dietary fiber. The solid material separated from the filtrate is then analyzed using various techniques to quantify the amount of dietary fiber.
Unfortunately, the filtering process is not always efficient and can allow significant amounts of dietary fiber to pass through with the filtrate, resulting in an under-quantification of the true dietary fiber content of the sample tested. For manufacturers adding dietary fiber to a product, the under-quantification of dietary fiber content in a sample can cause a manufacturer to over-fortify their products with fiber during production in an effort to meet a target level of fiber content. If the true dietary fiber content of a sample could be more accurately measured, the manufacturer could more precisely control the amount of dietary fiber added to the product during manufacture.